Acta Protozool. (2016) 55: 249–257 www.ejournals.eu/Acta-Protozoologica ACTA doi:10.4467/16890027AP.16.027.6096 PROTOZOOLOGICA Trichodinids (Ciliophora) of Corydoras paleatus (Siluriformes) and Jenynsia multidentata (Cyprinodontiformes) from Argentina, with Description of Trichodina corydori n. sp. and Trichodina jenynsii n. sp. Paula S. MARCOTEGUI1, Linda BASSON2, and Sergio R. MARTORELLI1 1 Centro de Estudios Parasitológicos y de Vectores (CEPAVE) (CCT-La Plata-CONICET-UNLP), Argentina; 2 Department of Zoology and Entomology, University of the Free State, Bloemfontein, Republic of South Africa Abstract. During surveys of parasites of the pepper cory Corydoras paleatus Jenyns, 1842 and sided-livebearer Jenynsia multidentata Jenyns, 1842 from Samborombón River, Argentina, Trichodina corydori n. sp., Trichodina cribbi Dove and O’Donoghue, 2005 and T. je- nynsii n. sp. were morphologically studied. Taxonomic and morphometric data for these trichodinids based on dry silver nitrate-impregnated specimens are presented. Trichodina corydori is characterized by a prominent blade apophysis, the section connecting the blade and central part is short, and the adoral ciliary spiral makes a turn of 370–380°. Trichodina jenynsii is characterized by curved blades and prominently- shaped denticle rays that are characteristically extremely long, tapering to thin sharp points in adult specimens. This study is the first formal report of these trichodinids from South America, and the description of two new species. Key words: Ciliophora, Trichodina, fish parasites, gill parasites, trichodinids, Argentina. INTRODUCTION mccradyi (Mayer) (Martorelli et al. 2008). Marcotegui and Martorelli (2009) described Trichodina scalensis Marcotegui et Martorelli, 2009 from Mugil liza (Va- Trichodinid ciliophorans have rarely been studied in lenciennes), and reported Trichodina puytoraci Lom, South America (Martins and Ghiraldelli 2008, Miranda 1962, T. lepsii Lom, 1962, T. jadranica (Raabe, 1958) et al. 2012, Hashimoto et al. 2016). Several authors re- from the same host, and T. murmanica Polyanski, 1955, ported Trichodina spp. from Argentina, but formal de- Diparitella simpex Raabe, 1959 from Micropogonias scriptions were not made (Viozzi 1996, Cremonte and furnieri (Desmarest) from brackish-waters. Thus far no Figueras 2004, Cremonte et al. 2005). The only single trichodinids have been described from freshwater fish marine species formally described from Argentinian wa- in Argentina. ters is Trichodina marplatensis Martorelli, Marcotegui The pepper cory, Corydoras paleatus (Jenyns) is na- et Alda, 2008, found on the ctenophore Mnemiopsis tive of southern Brazil, Uruguay, Paraguay and Argen- tina, inhabiting rivers, tributaries and standing waters Address for correspondence: Paula S. Marcotegui, Boulevard 120, No. 1460 e/61 (B1902CHX) La Plata, Buenos Aires, Argentina. including pools and small lakes. This species is a very Phone: 054-221-4233471; Fax: 054-221-4232327; e-mail: pmarco- good choice for the community aquarium, because it is [email protected] a hardy, good looking, and peaceful fish. 250 P. S. Marcotegui et al. The one-sided livebearer Jenynsia multidentata (Je- hesive disc diameter, 27.7–37.0 (32.1±2.6); diameter nyns) is a viviparous fish, showing the broadest distri- of denticulate ring, 16.2–23.3 (20.4±1.7); width of bution of its genus, ranging from the Atlantic coastal border membrane, 1.8–3.3 (2.9±0.4); denticle number, drainages from the Rio Negro Province (Argentina) to 23–27 (24); number of radial pins per denticle, 8–10 the city of Rio de Janeiro, Brazil (Ghedotti and Weitz- (10); denticle span, 8.0–10.7 (9.2±0.7); denticle length, man 1996). 2.8–4.7 (3.8±0.6); central zone of adhesive disc dark; The aim of this paper is to report on three species of blade length, 3.4–4.4 (3.8±0.2). Anterior blade margin trichodinids from freshwater C. paleatus and J. multi- strongly rounded, curving into very prominent blade dentata, and to describe two new species from both apophysis. Distal margin of blade rounded with blade these hosts collected in the Samborombón River (Bue- filling most of space between Y-axes. Distal blade nos Aires, Argentina). Furthermore, the present com- margin with strong curve towards blunt and rounded munication reports on the morphological characteris- tangent point. Apex of blade not touching Y+1 axis. tics based on silver nitrate-impregnated preparations of Posterior blade margin shallow, becoming deeper to- these species. wards central part. Section connecting the blade and central part short, but well developed. Central part well developed with rounded tip, fitting tightly into preced- MATERIALS AND METHODS ing denticle. Central part extending more than halfway to Y-1 axis. Shape of central part above and below the Fish were collected from the Samborombón River (Buenos Ai- X-axis very similar. Central part width 1.0–1.9 (1.4± res, Argentina) (35°10′39.79″S and 58°15′29.70″W) between April 0.3). Rays strongly developed, starting more narrow 2013 and August 2013. A total of 32 specimens of C. paleatus and from central part, becoming slightly thicker towards 25 specimens of J. multidentata were examined. Skin and excised proximal ends. Some rays directed towards center of gills from freshly killed fish were examined under a dissecting mi- adhesive disc, some angled slightly anteriorly. Ray apo- croscope. Fresh skin and gill smears were made from the hosts. Smears with trichodinids were air dried and Foissner´s modifica- physis not visible. Ray connection not well developed. tions of Klein´s dry silver nitrate technique (Foissner 1992) was Point of ray bluntly and strongly rounded. Ray length used to impregnate the specimens to study the adhesive disc and its 3.5–5.1 (4.2±0.4). Ratio of denticle above to denticle elements. The sequence and method of the description of denticle below x axis 0.8–1. Adoral ciliary spiral makes a turn elements follow the recommendations of Lom (1958) and Van As of 370–380°. Macronucleus horseshoe-shaped, elon- and Basson (1992). Live specimens, stained with methylene blue or orcein, were used for nuclear observations and details of the infra- gated, external diameter is 30.7–34.3 (32.5±1.8), dis- ciliature. Examinations of prepared slides were made with a Olym- tance between ends 6.2–7.7 (7.1±0.6). Micronucleus pus BX51 microscope and the measurements were made with Image not observed. J software. The photomicrographs were taken using a microscope at Type host: Corydoras paleatus Jenyns, 1842 (Silu- 100 × magnification. riformes: Callichthyidae) The description of each species is based on 20 stained and Type locality: Samborombón River (Brand- mounted specimens. All measurements are presented in microme- tres; minimum and maximum values are given, followed in pa- sen), Buenos Aires, Argentina (35°10′39.79″S, rentheses by the arithmetic mean and standard deviation. In case 58°15′29.70″W) of number of denticles and radial pins per denticle, minimum and Site of infection: gills maximum values are given, followed in parentheses by the mode. Type specimens: MLP-Pr 98 The span of the denticle is measured from the tip of blade to the tip Etymology: The specific epithet “corydori” is of the ray. Body diameter is measured as the adhesive disc plus bor- der membrane. The type and voucher materials have been deposited coined from the name of host species. in the Museo de La Plata, Argentina, Invertebrate Collection (MLP, Remarks. Morphological features of specimens coll. Nos. MLP000 to MLP000). found in C. paleatus agree with typical for Paratrichodi- na. Thus, denticles have well-developed rays, and are wedged together only by central parts, if anterior pro- RESULTS jection present, is situated near the base of the blade and is not in contact with the notch in the blade of the pre- ceding denticle (Lom 1958, Basson and Van As 1989). Trichodina corydori n. sp. (Figs 1A–D; 4A) Lom and Haldar (1976) state that the upper limits of the Description. A small to medium-sized, freshwater adoral cilia in Trichodinella Šrámek-Hušek, 1963, Tri- trichodinid: body diameter, 33.9–42.3 (38.1±2.5); ad- partiella Lom, 1959 and Paratrichodina are 290°, and Trichodinids from Argentina 251 Fig. 1. Photomicrographs of Trichodina corydori n. sp. from Corydoras paleatus. A–B – Silver nitrate-impregnated adhesive discs. C – Methylene-blue staining of adoral ciliary spiral. D – and orcein stain of macronucleus. Scale bars: 10 μm. the lower limit in Trichodina is 330°. Nevertheless, the Tavares-Dias et al. (2013). However, T. corydori differs importance of the length of the adoral cilia as a generic from P. africana in the shape of the denticle, some other characteristic sometimes appears to be less distinct than measurements, as well as the adoral spiral: (1) The new previously thought. Recently the majority of described species is larger than P. africana, for example, in the ad- species have in effect been classified based on denti- hesive disc (27.7–37.0 vs. 12.2–25), and denticulate ring cle morphology alone (Gaze and Wootten 1999). The (16.2–23.3 vs. 5.7–16.5). (2) In the case of the new spe- adoral spiral in T. corydori n. sp. presents a turn of more cies, the ray length is similar to blade length, but in the than 330°, which falls in the range for Trichodina. case of P. africana the ray is shorter than the blade. (3) The denticle shape of T. corydori mostly resembles The ray is thicker in the new species than in P. africana. Paratrichodina africana Kazubski and El-Tantawy, 1986 (4) The section connecting the blade and the central part recently reported from wild and farmed Oreochromis is very short in the new species, but long in P. africana. niloticus (Linnaeus) in eastern Amazonia, Brazil by (5) The morphometric data of the new species also vary 252 P.